Qingqi He, The State Key Laboratory of Media Convergence and Communication, School of Information and Communication Engineering, Communication University of China, Beijing 100024 China, China; Qiang An, The department of Biomedical Engineering, Fourth Military Medical University, Xi’an 710032, China, China; Ahmad Hoorfar, The Antenna Research Laboratory, Center for Advanced Communications, Villanova University, Villanova, PA 19085 USA, United States